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Thread: led power draw to equal 315w cmh?

  1. #1

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    Default led power draw to equal 315w cmh?

    cmh is working well enough in my cupboard. ~45w psf. Quoted as 19umol/s per watt so near enough 600umol/s

    I've no interest in fancy stuff like being dimmable or varying the spectrum. If it's good enough for flowering, it's good enough for vegging. Only an on/off switch required.

    What sort of money am I looking at for a 600umol/s led?

    I want to work out how long the led takes to pay for itself in leccy savings. My cmh draws 320w from the wall.

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    I was looking to downgrade my electric bill for a while now as I want to go from 4 plants under 400w hps to just 1 or 2 but each time I look at LEDs for the size I need and budget I come away more confused

    Think I'll just get a 250w hps
    Gl farmer

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  5. #3

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    I'm not sure yet if I'm going to go led. I have enough cmh ballasts and bulbs to outlast me so leccy savings would be the only reason to change.

    How long before those savings equal the cost of the led though?

    If you can find a used 315w cmh cheap enough, give it a try. Better growing than a 400w hps and less heat.

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    Most 315cmh pull 340w (93% efficient ballast, not many beat that)

    System efficacy for cmh is closer to 1.6 at best. 1.9 is dodgy marketing (bulb only fugure). Migro measured his CMH at 1.3umol overall.

    Cheaper high end LED will save at 35% running costs pulling with 2.5+ umol system

    High end LED will save 45% running costs with 2.95 system umol

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    My cmh measured 320w but it's a cheapo meter. The 8" rvk running at 40% + filter measured 80w.

    Where led also wins on specs imo is the angle of lighting. Something like 110 degrees iirc. With hid, not much of the light goes direct from bulb to leaf. The rest hits the reflector and/or the walls first. With led, not much light seems to hit the wall.

    A 45% saving in running costs would be nice. Especially if growing autos at 24/0. Call it 333w draw, that's 56 kw/hr per week. £10.64 with my supplier, including 5% vat. A 45% saving is £4.79 a week. Over 2 years that's a tad under £500.

    Will £500 get a high end led?

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  11. #6

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    Quote Originally Posted by Farmer Geddon View Post
    My cmh measured 320w but it's a cheapo meter. The 8" rvk running at 40% + filter measured 80w.

    Where led also wins on specs imo is the angle of lighting. Something like 110 degrees iirc. With hid, not much of the light goes direct from bulb to leaf. The rest hits the reflector and/or the walls first. With led, not much light seems to hit the wall.

    A 45% saving in running costs would be nice. Especially if growing autos at 24/0. Call it 333w draw, that's 56 kw/hr per week. £10.64 with my supplier, including 5% vat. A 45% saving is £4.79 a week. Over 2 years that's a tad under £500.

    Will £500 get a high end led?

    What size is your groom? $500.00 is plenty for a high end lamp.

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    Id go with a 350R that Blue uses, its 2.8 umol and will exceed a 600 hps at 300 odd watts with over 900umol. Ive been looking at one for a while. At 200watts the efficiency will be huge.

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    The 350R looks a nice light. At 35", it's just a bit too long for my space. 34" x 32". An 80cm square garden tray fits the space with not much to spare. Is there a reason why the 350R has that gap in the middle?

    The HLG 260W would fit. What's the difference between the 260W kit and the 260w XL kit?

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  17. #9

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    Cutting all the bullshit out you heard the expression
    You can't fix what isn't broke

    What might equal or out perform on paper might not work for you.
    I've had experience with both and reckon performance is similar but both have different approaches in environments and hunger
    It's not just the light that performs for you imho


    Sent from my iPhone using Tapatalk

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    Good points BG. cmh is pretty much a direct replacement for hps. Better and cooler but no real change as to how the grow is done. led is a different technology.

    What were the different approaches you used with cmh and led?

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